ABSTRACT
BACKGROUND: Cardiac myxoma is the most common benign cardiac tumor. Its tremendous size and fragile character severely bother the surgeons. Several minimal invasive approaches had been applied for radical tumor excision. The wound was forcibly enlarged for en-bloc specimen removal and prevention of debris sputtering. CASE PRESENTATION: We reported a case of huge tricuspid valve (TV) myxoma managed by robot-assisted endoscopic tumor resection and TV repair, with initial presentation of worsening shortness of breath for two months. The tumor was downsized with a morcellator and removed through a keyhole wound (1.1 cm in diameter). The patient recovered uneventfully and was discharged after four days. CONCLUSIONS: With the first morcellator application, this might be the smallest surgical wound reported after the removal of a huge cardiac myxoma. The ICU and hospital stays were shortened. This might be effectively applied to further minimally invasive surgeries for cardiac tumor excision.
Subject(s)
Heart Neoplasms , Myxoma , Robotics , Endoscopy , Heart Neoplasms/diagnostic imaging , Heart Neoplasms/surgery , Humans , Myxoma/diagnostic imaging , Myxoma/surgery , Tricuspid Valve/surgeryABSTRACT
Background Mitral regurgitation (MR) is a major contributor for heart failure (HF) and atrial fibrillation. Despite the advancement of MR surgeries, an effective medical therapy to mitigate MR progression is lacking. Sodium glucose cotransporter 2 inhibitors, a new class of antidiabetic drugs, has shown measurable benefits in reduction of HF hospitalization and cardiovascular mortality but the mechanism is unclear. We hypothesized that dapagliflozin (DAPA), a sodium glucose cotransporter 2 inhibitor, can improve cardiac hemodynamics in MR-induced HF. Methods and Results Using a novel, mini-invasive technique, we established a MR model in rats, in which MR induced left heart dilatation and functional decline. Half of the rats were randomized to be administered with DAPA at 10 mg/kg per day for 6 weeks. After evaluation of electrocardiography and echocardiography, hemodynamic studies were performed, followed by postmortem tissue analyses. Results showed that DAPA partially rescued MR-induced impairment including partial restoration of left ventricular ejection fraction and end-systolic pressure volume relationship. Despite no significant changes in electrocardiography at rest, rats treated with DAPA exhibited lower inducibility and decreased duration of pacing-induced atrial fibrillation. DAPA also significantly attenuated cardiac fibrosis, cardiac expression of apoptosis, and endoplasmic reticulum stress-associated proteins. Conclusions DAPA was able to suppress cardiac fibrosis and endoplasmic reticulum stress and improve hemodynamics in an MR-induced HF rat model. The demonstrated DAPA effect on the heart and its association with key molecular contributors in eliciting its cardio-protective function, provides a plausible point of DAPA as a potential strategy for MR-induced HF.
Subject(s)
Arrhythmias, Cardiac/drug therapy , Benzhydryl Compounds/pharmacology , Glucosides/pharmacology , Hemodynamics/physiology , Mitral Valve Insufficiency/complications , Animals , Arrhythmias, Cardiac/etiology , Arrhythmias, Cardiac/physiopathology , Disease Models, Animal , Hemodynamics/drug effects , Male , Mitral Valve Insufficiency/physiopathology , Rats , Rats, Sprague-Dawley , Sodium-Glucose Transporter 2 Inhibitors/pharmacologyABSTRACT
Right ventricular impairment is a predictor of cardiovascular outcomes in patients with degenerative mitral regurgitation. However, the time course of right ventricular functional changes post-surgical mitral valve repair remains largely unknown. Herein, using right ventricular-focused echocardiography, we aimed to investigate right ventricular reserve and its impact on hospitalization for heart failure after mitral valve repair. In this prospective study, we enrolled 108 patients scheduled to undergo surgical repair of degenerative mitral regurgitation. Echocardiography, including right ventricular strain analysis, was performed prior to, and one month and six months post mitral valve repair. Right ventricular strain that improved one month post-surgery was defined as reserved right ventricular. In addition, any cardiovascular outcomes comprising heart failure that required admission were recorded. The median follow-up duration is 31 months. Despite a significant improvement in mitral valve regurgitant volume post-operatively, left ventricular ejection fraction (LVEF) at six months was similar to LVEF at baseline. There was a transient decrease in LV longitudinal strain at one month that was recovered six months post mitral valve repair. Regarding the right ventricular, in contrast with conventional right ventricular parameters, including right ventricular tissue Doppler S', fractional area change and tricuspid annular plane systolic excursion (TAPSE), only resolution of right ventricular strain at one month predicted the subsequent myocardial recovery. Furthermore, patients with reserved right ventricular had a lower risk of hospitalization for heart failure compared to those with non-reserved right ventricular. Collectively, the early resolution of right ventricular strain is associated with the improvement in right ventricular function (measured by TAPSE) and in heart failure hospitalization in patients who had undergone surgical mitral valve repair for degenerative mitral regurgitation.
ABSTRACT
OBJECTIVE: The need for anticoagulation treatment following bioprosthetic aortic valve replacement remains controversial. We investigated the associations of warfarin treatment with the risks of major adverse cardiac and cerebrovascular events, including mortality, bleeding incidents, and reoperation requirement after bioprosthetic aortic valve replacement surgery. METHODS: We identified 1086 patients who received first bioprosthetic aortic valve replacement between 2001 and 2010 using Taiwan's National Health Insurance Database. Patients were excluded for prior use of warfarin, warfarin use for >3 months, dual valve procedures, prior valve surgeries, or concomitant surgeries. Enrolled patients were divided into 2 groups according to whether they were warfarin-naïve or received warfarin for <3 months postsurgery. After propensity score matching, 282 patients not receiving warfarin were matched to 282 patients receiving warfarin for <3 months. Patients were followed-up for minimum 36 months. RESULTS: Patients receiving warfarin were younger and showed less frequent kidney disease than those who did not use warfarin. The warfarin group demonstrated a gross decrease in major adverse cardiac and cerebrovascular events. Patients receiving warfarin for <30 days were at an even lower risk for major adverse cardiac and cerebrovascular events than those treated for ≥30 days. No significant difference in bleeding or reoperation risk was observed between warfarin users and warfarin nonusers. Similar findings remained after propensity-score matching but the benefit of short-term warfarin use diminished in a younger population. CONCLUSIONS: Short-term use of postoperative warfarin (especially <30 days) following bioprosthetic aortic valve replacement may be associated with a reduction in MACCE compared with nonuse.
Subject(s)
Anticoagulants/administration & dosage , Aortic Valve/surgery , Bioprosthesis , Cerebrovascular Disorders/prevention & control , Heart Diseases/prevention & control , Heart Valve Prosthesis Implantation/instrumentation , Heart Valve Prosthesis , Warfarin/administration & dosage , Adolescent , Adult , Aged , Aged, 80 and over , Anticoagulants/adverse effects , Aortic Valve/diagnostic imaging , Aortic Valve/physiopathology , Cerebrovascular Disorders/diagnosis , Cerebrovascular Disorders/etiology , Cerebrovascular Disorders/mortality , Databases, Factual , Drug Administration Schedule , Female , Heart Diseases/diagnosis , Heart Diseases/etiology , Heart Diseases/mortality , Heart Valve Prosthesis Implantation/adverse effects , Heart Valve Prosthesis Implantation/mortality , Hemorrhage/chemically induced , Humans , Male , Middle Aged , Prosthesis Design , Retrospective Studies , Risk Assessment , Risk Factors , Taiwan , Time Factors , Treatment Outcome , Warfarin/adverse effects , Young AdultABSTRACT
Transcatheter heart valve-in-valve implantation in failed surgical bioprosthetic valves has shown promising outcomes, prompting the stepwise expansion of their applications in different clinical scenarios. Recently, there is increased interest in valve-in-valve techniques for the treatment of patients with complex congenital heart disease. Herein, we report a case of successful transapical transcatheter atrioventricular valve-in-valve implantation in a patient with Fontan circulation and dextrocardia. The patient was previously treated with total cavopulmonary connection and atrioventricular valve replacement with recurrent prosthesis dysfunction.
Subject(s)
Bioprosthesis , Cardiac Catheterization/methods , Dextrocardia/surgery , Fontan Procedure/methods , Heart Valve Diseases/surgery , Heart Valve Prosthesis Implantation/methods , Heart Valves/surgery , Adult , Dextrocardia/diagnosis , Female , Heart Valve Diseases/diagnosis , Humans , Prosthesis Design , Tomography, X-Ray ComputedABSTRACT
OBJECTIVES: Robotic mitral valve replacement (MVR) emerged in the late 1990s as an alternative approach to conventional sternotomy. With the increased use of bioprosthetic valves worldwide and strong patient desire for minimally invasive procedures, the safety and feasibility of robotic MVRs with bioprosthetic valves require investigation. METHODS: Between January 2013 and May 2017, 52 consecutive patients underwent robotic MVRs using the da Vinci Si surgical system (Intuitive Surgical Inc., Sunnyvale, CA, USA). Their mean age was 55.1 ± 13.8 years, and mean EuroSCORE II was 2.25% ± 1.25%. Among the enrolled patients, 32 (61.5%) patients presented with preoperative atrial fibrillation, 6 (11.5%) patients had experienced embolic stroke and 5 (9.6%) patients had undergone previous cardiac surgery. The operations were performed using cardiopulmonary bypass (CPB) under an arrested heart status. RESULTS: Five porcine valves and 47 bovine valves were implanted. A total of 38 (73.1%) patients received concomitant cardiac procedures, including 26 Cox-maze IV procedures, 12 tricuspid valve repairs and 5 atrial septal defect repairs. The mean aortic cross-clamp and CPB times were 141.3 ± 34.3 min and 217.1 ± 42.0 min, respectively. There was no operative mortality. During the mean follow-up of 29 ± 15 months, no prosthesis degeneration was noted. The average left atrial dimension exhibited a significant decrease from 51.4 ± 11.5 mm to 42.6 ± 10.1 mm. CONCLUSIONS: Robotic MVR with bioprosthetic valves is safe, feasible and reproducible. Mid-term results are encouraging. Both aortic cross-clamp and CPB times can be improved with experience.
Subject(s)
Bioprosthesis , Heart Valve Prosthesis Implantation/methods , Heart Valve Prosthesis , Mitral Valve/surgery , Robotic Surgical Procedures/methods , Adult , Aged , Echocardiography , Feasibility Studies , Female , Heart Valve Prosthesis Implantation/adverse effects , Heart Valve Prosthesis Implantation/instrumentation , Humans , Male , Middle Aged , Postoperative Complications , Prosthesis Design , Retrospective Studies , Robotic Surgical Procedures/adverse effects , Robotic Surgical Procedures/instrumentationABSTRACT
Anomalous origin of the right coronary artery (ARCA) from the left Valsalva sinus is a rare but known cause of sudden cardiac death. Surgical revascularization techniques include coronary artery bypass grafting, unroofing, and reimplantation. We report 4 patients who underwent robot-assisted totally endoscopic coronary artery bypass (TECAB) for ARCA as an alternative surgical option. In 3 patients, a single aortocoronary saphenous vein bypass was performed, and in 1 patient the right internal mammary artery was used. All grafts are patent as shown by computed tomographic angiography or cardiac catheterization. We claim that totally endoscopic coronary artery bypass is feasible and safe for anomalous origin of the right coronary artery.
Subject(s)
Coronary Artery Bypass/methods , Coronary Vessel Anomalies/surgery , Coronary Vessels/surgery , Endovascular Procedures/methods , Adult , Coronary Angiography/methods , Coronary Vessel Anomalies/diagnosis , Coronary Vessels/diagnostic imaging , Female , Humans , Male , Tomography, X-Ray ComputedABSTRACT
Isolated ostial stenosis (IOS) is a rare disease that encroaches on aorto-coronary junction of uncertain etiology. All distal coronary vessels present normally. IOS occurs predominantly in premenopausal young women with few risk factors for atherosclerotic disease. Here, we report a 40-year-old woman who had experienced crescendo angina for 4 months. Surgical revascularization was achieved by robotic totally endoscopic coronary artery bypass (TECAB) with left internal thoracic artery (LITA) graft. She resumed her daily tasks without difficulties 1 week after the operation. Postoperative computed tomographic angiography disclosed good opacification of the LITA graft and distal runoff. Robotic TECAB is a potentially feasible alternative for IOS patients, particularly in premenopausal young woman, with obvious benefits of cosmetic appearance and speedy recovery.
ABSTRACT
OBJECTIVE: We attempted to test the hypothesis that preinduction of heat shock protein (HSP) 72 in the heart would improve left ventricular performance in rat heatstroke. METHODS: Cardiac expression of HSP 72 was quantitatively evaluated by western blot analysis in rats 0h, 12h, or 72h after mild heat preconditioning (MHP; 43°C for 30min). They were subjected to severe heat stress (SHS; 43°C for 70min) to induce heatstroke. A 1.2F catheter-tip pressure transducer was inserted into the left ventricle of these group rats under general anesthesia to record hemodynamic in the closed chest with a pressure-volume loop module data recording and analysis system. RESULTS: At the time point of heatstroke onset, compared with normothermic controls, group rats with 12h post-MHP had significantly increased cardiac HSP 72, decreased hyperthermia, decreased hypotension, decreased bradycardia, increased end-systolic pressure, increased end-diastolic pressure, increased stroke volume, decreased end-systolic volume, decreased end-diastolic pressure, increased cardiac output, increased ejection fraction, increased stroke work, increased arterial elastance, and decreased time constant of fall in ventricular pressure by Glantz-methods. With the loss of cardiac HSP 72 expression observed at 72h in post-MHP group rats, an insignificant protection against left ventricular performance was observed. CONCLUSION: Preinduction of cardiac HSP 72 may improve hypotension in heatstroke rats by increasing both cardiac mechanical efficiency and arterial elastance.
Subject(s)
Blood Pressure/physiology , HSP72 Heat-Shock Proteins/biosynthesis , Heart Rate/physiology , Heat Stroke/metabolism , Hypotension/metabolism , Ventricular Function, Left/physiology , Animals , Heat Stroke/physiopathology , Hypotension/physiopathology , Male , Random Allocation , Rats , Rats, Sprague-Dawley , Stroke Volume/physiologyABSTRACT
ß-amyloid (Aß)-mediated neuronal apoptosis contributes to the pathogenesis of Alzheimer's disease (AD). This study aimed to investigate whether astragalosides (AST) could inhibit Aß-induced apoptosis in vivo and in vitro and to explore the underlying mechanisms. Amyloid ß-protein fragment 25-35 (Aß25-35) was administered to cerebral lateral ventricle of rats to make the AD models in vivo. AST was able to attenuate both cortical cell degeneration and memory deficits in the AD rats. AST also inhibited Aß25-35-induced cytotoxicity (e.g., decreased cell viability); apoptosis (e.g., increased caspase-3 expression, increased DNA fragmentation, and Tau hyperphosphorylation); synaptotoxicity (e.g., increased loss of both a dendritic marker, microtubule-associated protein 2 (MAP-2) and synaptic proteins, synaptophysins); and mitochondrial dysfunction (e.g., increased mitochondrial membrane potential) in cultured primary rat cortical cells. The beneficial effect of AST in reducing Aß-induced cytotoxicity, apoptosis, and mitochondrial dysfunction in cortical cells were blocked by inhibition of phosphoinositide 3-kinase (PI3K)-dependent protein kinase B (PKB, as known as AKT) activation with LY294002. In addition, inhibition of extracellular protein kinase (ERK) with U0126 shared with the AST the same beneficial effects in reducing Aß-induced apoptosis. Our data suggest that the cortical PI3K/AKT and MAPK (or ERK) pathways as appealing therapeutic targets in treating AD, and AST may have a positive impact on AD treatment via modulation of both PI3K/AKT and ERK pathways.
Subject(s)
Alzheimer Disease/drug therapy , Alzheimer Disease/pathology , Amyloid beta-Peptides/toxicity , Cerebral Cortex/pathology , Saponins/therapeutic use , Alzheimer Disease/complications , Animals , Apoptosis/drug effects , Butadienes/pharmacology , Caspase 3/metabolism , Cells, Cultured , Extracellular Signal-Regulated MAP Kinases/metabolism , Male , Memory Disorders/complications , Memory Disorders/drug therapy , Memory Disorders/pathology , Mitochondria/drug effects , Mitochondria/metabolism , Nerve Degeneration/drug therapy , Nerve Degeneration/pathology , Neurons/drug effects , Neurons/pathology , Nitriles/pharmacology , Phosphorylation/drug effects , Proto-Oncogene Proteins c-akt/metabolism , Rats, Sprague-Dawley , Saponins/pharmacology , Synapses/drug effects , Synapses/metabolism , tau Proteins/metabolismABSTRACT
BACKGROUND/PURPOSE: The primary goal of this study was to test whether high-altitude exposure (HAE: 0.9% O(2) at 0.47 ATA for 24 hours) was capable of increasing the systemic inflammatory markers as well as the toxic organ injury indicators in rats, with a secondary goal to test whether preinduction of heat shock protein (HSP) 70 by hypobaric hypoxia preconditioning (HHP: 18.3% O(2) at 0.66 ATA for 5 h/day on 5 days consecutively for 2 weeks) attenuated the proposed increased serum levels of both the systemic inflammatory markers and the toxic organ injury indicators. METHODS: Rats were assigned to: (1) non-HHP (21% O(2) at 1.0 ATA)+non-HAE (21% O(2) at 1.0 ATA) group; (2) non-HHP+HAE group; (3) HHP+non-HAE group; (4) HHP+HAE group; and (5) HHP+HSP70 antibodies (Ab)+HAE group. For the HSP70Ab group, a neutralizing HSP70Ab was injected intravenously at 24 hours prior to HAE. All the physiological and biochemical parameters were obtained at the end of HAE or the equivalent time period of non-HAE. Blood samples were obtained for determination of both the systemic inflammatory markers (e.g., serum tumor necrosis factor-α, interleukin-1ß, E-selectin, intercellular adhesion molecule-1, and liver myeloperoxidase activity) and the toxic organ injury indicators (e.g., nitric oxide metabolites, 2,3-dihydroxybenzoic acid, and lactate dehydrogenase). RESULTS: HHP, in addition to inducing overexpression of tissue HSP70, significantly attenuated the HAE-induced hypotension, bradycardia, hypoxia, acidosis, and increased tissue levels of both the systemic inflammatory markers and the toxic organ injury indicators. The beneficial effects of HHP in inducing tissue overexpression of HSP70 as well as in preventing the HAE-induced increased levels of the systemic inflammatory markers and the toxic organ injury indicators could be significantly reduced by HSP70Ab preconditioning. CONCLUSION: These results suggest that HHP may downgrade both the systemic inflammatory markers and the toxic organ injury indicators in HAE by upregulating tissue HSP70.
Subject(s)
Altitude Sickness/blood , Biomarkers/blood , HSP70 Heat-Shock Proteins/administration & dosage , Animals , Disease Models, Animal , E-Selectin/blood , Hydroxybenzoates/blood , Nitric Oxide/metabolism , Rats , Rats, Sprague-Dawley , Tumor Necrosis Factor-alpha/bloodABSTRACT
Ischemic and oxidative damage to the hypothalamus may be associated with decreased heat tolerance as well as heatstroke formation. The present study explores the hypothalamic proteome mechanisms associated with heatstroke-mediated hypothalamic ischemia, and oxidative damage. Heatstroke rats had hypotension, hypothalamic ischemia, and lethality. In addition, they had hyperthermia and hypothalamic blood-brain-barrier disruption, oxidative stress, activated inflammation, and neuronal apoptosis and degeneration. 2DE combined LC-MS/MS revealed that heatstroke-induced ischemic injury and apoptosis were associated with upregulation of L-lactate dehydrogenase but downregulation of both dihydropyriminase-related protein and 14-3-3 Zeta isoform protein. Heat-induced blood-brain-barrier disruption might be related to upregulation of glial fibrillary acidic protein. Oxidative stress caused by heatstroke might be related to upregulation of cytosolic dehydrogenase-1. Also, heat-induced overproduction of proinflammatory cytokines might be associated with downregulation of stathmin 1. Heat-induced hypothalamic ischemia, apoptosis, injury (or upregulation of L-lactate dehydrogenase), blood-brain-barrier disruption (or upregulation of glial fibrillary acidic protein), oxidative stress (or upregulation of cytosolic dehydrogenase-1), and activated inflammation (or downregulation of stathmin 1) were all significantly reversed by whole body cooling. Our data indicate that cooling therapy improves outcomes of heatstroke by modulating hypothalamic proteome mechanisms.
Subject(s)
Heat Stroke/metabolism , Hypothalamus/metabolism , Hypothalamus/physiopathology , Proteome/analysis , Animals , Cytokines/metabolism , Electrophoresis, Gel, Two-Dimensional , Enzyme-Linked Immunosorbent Assay , Heat Stroke/mortality , Heat Stroke/physiopathology , Hydroxybenzoates/metabolism , Hypothermia, Induced , Neurons/metabolism , Neurons/pathology , Nitric Oxide/metabolism , Oxidative Stress , Rats, Sprague-Dawley , Tandem Mass SpectrometryABSTRACT
Cathepsin B is one of the major lysosomal cysteine proteases that plays an important role in apoptosis. Herein, we investigated whether Cathepsin B is involved in cardiomyocyte apoptosis caused by hyperthermic injury (HI) and heat shock protein (HSP)-70 protects these cells from HI-induced apoptosis mediated by Cathepsin. HI was produced in H9C2 cells by putting them in a circulating 43 °C water bath for 120 min, whereas preinduction of HSP-70 was produced in H9C2 cells by mild heat preconditioning (or putting them in 42 °C water bath for 30 min) 8 h before the start of HI. It was found that HI caused both cardiomyocyte apoptosis and increased Cathepsin B activity in H9C2 cells. E-64-c, in addition to reducing Cathepsin B activity, significantly attenuated HI-induced cardiomyocyte apoptosis (evidenced by increased apoptotic cell numbers, increased tuncated Bid (t-Bid), increased cytochrome C, increased caspase-9/-3, and decreased Bcl-2/Bax) in H9C2 cells. In addition, preinduction of HSP-70 by mild heat preconditioning or inhibition of HSP-70 by Tripolide significantly attenuated or exacerbated respectively both the cardiomyocyte apoptosis and increased Cathepsin B activity in H9C2 cells. Furthermore, the beneficial effects of pre-induction of HSP-70 by mild heat production in reducing both cardiomyocyte apoptosis and increased Cathepsin B activity caused by HI can be significantly reduced by Triptolide preconditioning. These results indicate that Cathepsin B is involved in HI-induced cardiomyocyte apoptosis in H9C2 cells and HSP-70 protects these cells from HI-induced cardiomyocyte apoptosis through Cathepsin B pathways.
Subject(s)
Apoptosis , Cathepsin B/metabolism , HSP70 Heat-Shock Proteins/metabolism , Heat-Shock Response , Myocytes, Cardiac/metabolism , Animals , Apoptosis Regulatory Proteins/metabolism , Cell Line , Diterpenes/pharmacology , Epoxy Compounds/pharmacology , HSP70 Heat-Shock Proteins/antagonists & inhibitors , Hot Temperature , Myocytes, Cardiac/cytology , Phenanthrenes/pharmacology , RatsABSTRACT
It remains unclear whether etanercept penetrates directly into the contused brain and improves the outcomes of TBI by attenuating brain contents of TNF- α and/or stimulating newly formed neurogenesis. Rats that sustained TBI are immediately treated with etanercept. Acute neurological and motor injury is assessed in all rats the day prior to and 7 days after surgery. The numbers of the colocalizations of 5-bromodeoxyuridine and doublecortin specific markers in the contused brain injury that occurred during TBI were counted by immunofluorescence staining. Enzyme immunoassay for quantitative determination of TNF-α or etanercept in brain tissues is also performed. Seven days after systemic administration of etanercept, levels of etanercept can be detected in the contused brain tissues. In addition, neurological and motor deficits, cerebral contusion, and increased brain TNF-α contents caused by TBI can be attenuated by etanercept therapy. Furthermore, the increased numbers of the colocalizations of 5-bromodeoxyuridine and doublecortin specific markers in the contused brain tissues caused by TBI can be potentiated by etanercept therapy. These findings indicate that systemically administered etanercept may penetrate directly into the contused brain tissues and may improve outcomes of TBI by reducing brain contents of TNF- α and by stimulating newly formed neurogenesis.
Subject(s)
Brain Injuries/drug therapy , Brain Injuries/metabolism , Immunoglobulin G/therapeutic use , Receptors, Tumor Necrosis Factor/therapeutic use , Tumor Necrosis Factor-alpha/metabolism , Animals , Doublecortin Protein , Etanercept , Immunoenzyme Techniques , Male , Neurogenesis/drug effects , Random Allocation , Rats , Rats, Sprague-DawleyABSTRACT
PURPOSE: We sought to assess whether heat-induced autophagy, apoptosis and cell damage in H9c2 cells can be affected by pre-inducing HSP70 (heat shock protein 70). MATERIALS AND METHODS: Cell viability was determined using 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide staining and a lactate dehydrogenase assay. Apoptosis was evidenced using both flow cytometry and counting caspase-3 positive cells, whereas autophagy was evidenced by the increased LC3-II expression and lysosomal activity. RESULTS: The viability of H9c2 cells was temperature-dependently (40-44 °C) and time-dependently (90-180 min) significantly (p < 0.05) reduced by severe heat, which caused cell damage, apoptosis and autophagy. Heat-induced cell injury could be attenuated by pretreatment with 3-methylademine (an autophagy inhibitor) or Z-DEVD-FMK (a caspase-3 inhibitor). Neither apoptosis nor autophagy over the levels found in normothermic controls was induced in heat-shock preconditioned controls (no subsequent heat injury). The beneficial effects of mild heat preconditioning (preventing heat-induced cell damage, apoptosis and autophagy) were significantly attenuated by inhibiting HSP70 overexpression with triptolide (Tripterygium wilfordii) pretreatment. CONCLUSION: We conclude that pre-inducing HSP70 attenuates heat-stimulated cell autophagy, apoptosis and damage in the heart. However, this requires in vivo confirmation.
Subject(s)
HSP70 Heat-Shock Proteins , Heat-Shock Response , Myocytes, Cardiac/cytology , Adenine/analogs & derivatives , Adenine/pharmacology , Animals , Apoptosis , Autophagy , Caspase Inhibitors/pharmacology , Cell Line , Cell Survival , Diterpenes/pharmacology , Epoxy Compounds/pharmacology , Hot Temperature , Oligopeptides/pharmacology , Phenanthrenes/pharmacology , RatsABSTRACT
OBJECTIVE: We sought to assess the effect of therapeutic hypothermia on the autophagy that occurred in ischemia-reperfused (IR) H9c2 cardiomyocytes. METHODS: In control studies, the H9c2 cells at a density of 1 × 10(5) per culture dish in six-well plate were exposed to normoxic culture medium at 37 °C for 12h. All assays contained appropriate controls and were performed in triplicate and repeated on three separately initiated cultures. In hypothermia-treated group, the ischemic and hypoxic cells were maintained in a 32 °C incubation. The trypan blue exclusion method was used to assess the cell viability. Autophagy was evaluated by determining both the microtubule-associated protein 1 light chain 3 [LC3] levels and punctuate distribution of the autophagic vesicle associated form [LC3-II]. RESULTS: The results were mean ± standard error of mean of triplicates. The viable cell percentage for control group, IR group, and IR group treated with hypothermia at the start of ischemia, or reperfusion were 100% ± 9%, 20% ± 1%, 32% ± 3%, and 41% ± 3%, respectively. The cell death in I/R H9c2 cells was positively associated with increased LC3 levels and punctuate distribution of (LC3-II). Mild hypothermia adopted at the start of ischemia or reperfusion significantly reduced both the cell death and the autophagy in H9c2 cells. CONCLUSION: Our data indicate that in H9c2, IR stimulates cell autophagy and causes cell death, which can be attenuated by mild hypothermia. Our results, if further confirmed in vivo, may have important clinical implications during IR injury.